This invention relates to wedges, and more particularly relates to flanged wedges used by carpenters in connection with sawing or cutting boards.
Among the difficulties which may arise when sawing or cutting boards of some size and length are the problems which are attendant to the binding of the saw blade. Thus, in many sawing environments, the cut space (termed the "kerf") will close and pinch the saw blade before the sawing or cutting is completed, making the sawing extremely difficult, if not impossible. This phenomenon is termed "binding".
In the logging industry binding is a long known problem. Accordingly, wedges are often used to keep the kerf open and prevent the saw from binding. Frequently, the use of a wedge alone was insufficient since the log would roll or twist and either dislodge the wedge or otherwise position itself so as to still pinch the saw. To prevent this early loggers would place a wedge into the kerf and, then, embed an axe over or beside the wedge, perpendicular to the saw cut and thereby prevent rolling or twisting of the log relative to the wedge. Various types of finned or winged wedges have also become available for that purpose. See, for example, Gravel, U.S. Pat. No. 1,192,185 and Courville U.S. Pat. No. 3,515,372. In both of these patents the wings or fins on the wedge are designed to cut into the log at an angle perpendicular to the saw cut and thereby keep the log from rolling into a twist as the wedge is driven into the kerf. Another function of the wings or fins is to hold the wedge firmly in place and prevent it from dropping away above the saw before the cut is completed.
In that regard Gravel and Courville are similar to Eich U.S. Pat. No. 759,868. Eich discloses a wedge having parallel ribs or flanges formed on the wedge. These ribs or flanges enter the kerf in the timber and embed themselves in the wood sufficiently to retain the wedge in position and prevent the same from being accidentally displaced when driving the wedge.
With all of these prior wedge designs, the rigidity of the log is necessary in order for the fins to embed themselves. If the kerf spreads easily, the wedges will not function properly. The two sides of the kerf will not remain fixed with respect to each other and the wedge may still be dislodged.
Besides, in modern carpentry it is totally unacceptable to use a wedge having fins which are intended to embed themselves into the wood as the wedge is driven into the kerf. This would unduely damage any board which is intended to be used as a building material after cut to shape. Accordingly, carpenters frequently resort to the use of standard wedges, screw drivers, or other devices placed in the kerf to prevent binding of the saw. However, those devices are easily dislodged as the sawing progresses. Thus, the device will drop out of the kerf when the cut is so far into the board that the weight of the unsupported side of the board drops or moves that portion of the board out of the plane relative to the other side.
Accordingly, there is a need for a wedge that can be used to spread the kerf and yet remain fixed in place as the sawing progresses without damaging the board with embedded fins. Likewise, there is the need in modern carpentry to keep the board in one plane (preventing the unsupported sawed part from dropping or moving) and keeping the wedge aligned properly in relation to the board.